Conditionally exclude provided files based on last modified time

2 files changed, 24 insertions, 12 deletions

diff --git a/snekbox/memfs.py b/snekbox/memfs.py
index 34e696e..1a18e03 100644
--- a/snekbox/memfs.py
+++ b/snekbox/memfs.py
@@ -4,7 +4,7 @@ from __future__ import annotations
 import logging
 import warnings
 import weakref
-from collections.abc import Generator, Sequence
+from collections.abc import Generator
 from contextlib import suppress
 from pathlib import Path
 from types import TracebackType
@@ -121,7 +121,10 @@ class MemFS:
         return folder
 
     def files(
-        self, limit: int, pattern: str = "**/*", exclude_files: Sequence[str] = ()
+        self,
+        limit: int,
+        pattern: str = "**/*",
+        exclude_files: dict[Path, float] | None = None,
     ) -> Generator[FileAttachment, None, None]:
         """
         Yields FileAttachments for files found in the output directory.
@@ -129,13 +132,18 @@ class MemFS:
         Args:
             limit: The maximum number of files to parse.
             pattern: The glob pattern to match files against.
-            exclude_files: Files (relative to home directory) to exclude.
+            exclude_files: A dict of Paths and last modified times.
+                Files will be excluded if their last modified time
+                is equal to the provided value.
         """
         count = 0
         for file in self.output.rglob(pattern):
-            if str(file.relative_to(self.home)) in exclude_files:
-                log.info(f"Skipping excluded file {file!s}")
-                continue
+            if exclude_files and (orig_time := exclude_files.get(file)):
+                new_time = file.stat().st_mtime
+                log.info(f"Checking {file.name} ({orig_time=}, {new_time=})")
+                if file.stat().st_mtime == orig_time:
+                    log.info(f"Skipping {file.name} as it has not been modified")
+                    continue
             if count > limit:
                 log.info(f"Max attachments {limit} reached, skipping remaining files")
                 break
@@ -149,7 +157,7 @@ class MemFS:
         limit: int,
         pattern: str,
         preload_dict: bool = False,
-        exclude_files: Sequence[str] = (),
+        exclude_files: dict[Path, float] | None = None,
     ) -> list[FileAttachment]:
         """
         Return a sorted list of file paths within the output directory.
@@ -158,7 +166,9 @@ class MemFS:
             limit: The maximum number of files to parse.
             pattern: The glob pattern to match files against.
             preload_dict: Whether to preload as_dict property data.
-            exclude_files: Files (relative to home directory) to exclude.
+            exclude_files: A dict of Paths and last modified times.
+                Files will be excluded if their last modified time
+                is equal to the provided value.
         Returns:
             List of FileAttachments sorted lexically by path name.
         """
diff --git a/snekbox/nsjail.py b/snekbox/nsjail.py
index d425d35..57083e1 100644
--- a/snekbox/nsjail.py
+++ b/snekbox/nsjail.py
@@ -3,6 +3,7 @@ import re
 import subprocess
 import sys
 from collections.abc import Generator
+from pathlib import Path
 from tempfile import NamedTemporaryFile
 from typing import Iterable, TypeVar
 
@@ -226,9 +227,12 @@ class NsJail:
             ]
 
             # Write provided files if any
+            files_written: dict[Path, float] = {}
             for file in files:
                 try:
-                    file.save_to(fs.home)
+                    f_path = file.save_to(fs.home)
+                    # Save the written at time to later check if it was modified
+                    files_written[f_path] = f_path.stat().st_mtime
                     log.info(f"Created file at {(fs.home / file.path)!r}.")
                 except OSError as e:
                     log.info(f"Failed to create file at {(fs.home / file.path)!r}.", exc_info=e)
@@ -258,14 +262,12 @@ class NsJail:
             # convert negative exit codes to the `N + 128` form.
             returncode = -nsjail.returncode + 128 if nsjail.returncode < 0 else nsjail.returncode
 
-            # Exclude user uploaded files from output
-            to_exclude = [file.path for file in files]
             # Parse attachments with time limit
             try:
                 attachments = timed(
                     MemFS.files_list,
                     (fs, self.files_limit, self.files_pattern),
-                    {"preload_dict": True, "exclude_files": to_exclude},
+                    {"preload_dict": True, "exclude_files": files_written},
                     timeout=self.files_timeout,
                 )
                 log.info(f"Found {len(attachments)} files.")